This invention relates to railroad car positioning apparatus for moving one or more railroad cars along a track to a car unloading facility and involving a carriage movable parallel to the track at one side thereof and carrying means for engaging a single car or a train of coupled cars for advancing them to a predetermined position on the track. Typical prior art installations of this character are shown in the U.S. Pat. Nos. 3,695,185 to Blank, granted Oct. 3, 1972; No. 3,169,490 granted Feb. 16, 1965, to Saxonmeyer; No. 2,199,470 granted May 7, 1940, to Taylor; and No. 1,125,355 granted Jan. 19, 1915, to Lovell. The utility of such prior art car positioners was limited by the fact that they could not operate effectively both to move a single car or a train of two or more coupled cars from one end thereof and, also, to move a train of coupled cars by engaging the train between the cars. In the same coal unloading terminal, some trains to be unloaded may be of the "unit train" type, which are intended to remain coupled during unloading, and some trains may be made up of random railroad cars not equipped for unit train operation so that they must be uncoupled for unloading individually or in pairs, according to the character and capacity of the car unloader.
A more recent development in railroad car positioners is shown in U.S. Pat. No. Re. 27,300 granted Feb. 22, 1972, to Ludwig. The apparatus of that patent constituted an improvement on the apparatus of the aformentioned prior patents by providing means on the carriage for engaging a train of railroad cars between pairs of coupled cars for moving the entire train as required in the handling of trains of the aforementioned unit train type.
The present invention is an improvement in railroad car positioning apparatus of the type shown in the last-mentioned reissue patent to Ludwig and concerns the train engaging portion of the means on the carriage for engaging and moving the cars of a train. Unlike the apparatus of that prior patent to Ludwig, the coupler engaging assembly of the present invention is not only adapted for use between coupled railroad cars of the unit train, but is also adapted for use at either end of a single car or pair of coupled cars and between a pair of uncoupled cars in a versatile manner that enables a train of random cars to be advanced stepwise into and through a dumper, either one or two at a time according to the dumper capacity.